The semiconductor integrated circuit (IC) industry has experienced rapid growth. Technological advances in IC materials and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. However, these advances have increased the complexity of processing and manufacturing ICs and, for these advances to be realized, similar developments in IC processing and manufacturing are needed. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component that can be created using a fabrication process) has decreased. As lithographic features are reduced to below 40 nm, high numerical aperture processes are needed to overcome the resolution limit. The use of a trilayer films scheme appears to be promising in this regard.
In a trilayer films scheme, the contact angle of a middle layer is often mismatched with the contact angle of the photoresist layer. This can result in pattern peeling due to the deterioration of adhesion between the two layers. Another reason for pattern peeling may be an undercut profile that may be caused by non-uniform photoacid generator (PAG) distribution in the photoresist layer or the high reflectivity of the photoresist layer. Moreover, trench scum can result when PAG from the photoresist layer diffuses into the middle layer. Thus, a process and material that minimizes or removes these problems is desired.